1. Field of the Invention
The present invention relates generally to a mobile node (MN) for discovering a network to which the MN is handed over in a heterogeneous network environment, and method thereof. More specifically, the present invention relates to a mobile node (MN) and a network discovery method for discovering a neighbor network using neighbor information relating to neighbor point of attachments (PoAs) and activating only a communication interface corresponding to the discovered network.
2. Description of the Related Art
The prevalence of wireless Internet, the development of wireless communication technology, and the performance enhancement of portable computers lead to the increasing number of wireless Internet users. Under the wireless Internet environment, mobile nodes (MNs) are movable to other locations on occasion and thus change their point of attachment (PoA).
In case that a MN changes its location, communications in a current network environment need to be seamlessly maintained in a new network environment. In this regard, the idea of the handover is introduced. The handover is to hand communications over from an access node (AN) of the current network area to an AN of a next network area.
The MN may move into a wireless local area network (WLAN), a wireless metropolitan area network (WMAN), a cellular network, and so on. Generally, the WLAN environment conforms to Institute of Electrical and Electronics Engineers (IEEE) 802.11 standard, the WMAN environment conforms to IEEE 802.16 standard, and the cellular network environment conforms to 3rd Generation Partnership Project (3GPP) standard.
The MN needs to discover a neighbor PoA for the handover. To this end, the communication standard of the network environment informs the MN of information relating to a PoA corresponding to its network environment so that the MN can discover a proper access network.
However, the conventional method cannot be adopted universally to a heterogeneous network environment including the WLAN, the WMAN, and the cellular network.
The MN can be connected to networks by implementing various communication interfaces that support the IEEE 802.11 standard, the IEEE 802.16 standard, and the 3GPP standard. Accordingly, the MN discovers the entire neighbor networks using its communication interfaces prior to the handover. In detail, the MN broadcasts a network discovery message to its neighbors via the communications interfaces and then determines whether a response message is received. In other words, the handover requires that the MN maintain the entire communication interfaces in an active mode all the time, which causes high power consumption.
In the related art, the MN has to send a separate message to determine whether to change its IP network address in the handover ready process after the network discovery. As a result, the handover ready process takes a longer time and additional power consumption is needed.